Adopting a cat to give my lonely one some company. Need advice quick please?

Our cat we have now is rambunctious with high energy and is showing signs of under stimulation. My boyfriend and I are extremely busy, so we were thinking of getting him a friend. The shelter has a mama cat and her babies. Would it be better to adopt mama and one of her babies? Is it smart when we already have a little shit of a cat at home? I don’t know if she will become extremely protective with him around and shit will go down. We have a couple hours left to go back and adopt her…